package kata.wordwrap.a20110716;

/**
  * Word Wrap Kata.
  * Copyright (c) 2011, Peter Kofler, licensed under BSD License.
  */
public class WordWrapLoopBuffer {

   private static final char BLANK = ' ';
   private static final char NEWLINE = '\n';

   public static String wrap(String line, int maxLineLen) {
      StringBuilder accumulator = new StringBuilder(calcMaxSize(line.length(), maxLineLen));
      accumulator.append(line);

      int pos = 0;
      int inserted = 0;
      while (pos + maxLineLen < line.length()) {
         final int indexOfBlank = line.lastIndexOf(BLANK, pos + maxLineLen);
         if (indexOfBlank > pos - 1) {
            accumulator.setCharAt(inserted + indexOfBlank, NEWLINE);
            pos = indexOfBlank + 1;
         } else {
            accumulator.insert(inserted + pos + maxLineLen, NEWLINE);
            pos = pos + maxLineLen;
            inserted++;
         }
      }

      return accumulator.toString();
   }

   /**
    * Calc a bigger buffer so we never resize.
    */
   private static int calcMaxSize(int lineLen, int maxLineLen) {
      final int maxCharsAdded = lineLen / maxLineLen;
      return lineLen + maxCharsAdded;
   }

   /*
    * Like optimized loop solution, but
    * 1 Strings are created
    * 1 StringBuilders are created
    * -> constant objects created
    */

}